Formed film is used in the manufacture of many goods. It begins as a polymer (or polymers) extruded through a die. The polymer is extruded, forming a melt curtain, which is a relatively continuous flat surface.
The melt curtain starts crystallization or solidification of the polymer. This crystallized or solidified (depending upon the polymer) polymer may be referred to as a web or film. Treatment of that web or film (called film hereinafter) such as aperturing, etc., results in a formed film. The formed film may be used for any number of objects as desired, such as, for example, layers in laminates, etc.
It has been generally desired to maintain a smooth flow with little or no turbulence in the transition of the polymer from melt curtain to film. This results, without further treatment, in a formed film with a relatively uniform surface and/or appearance.